KR20090087932A - Neutralizer - Google Patents

Abstract

A neutralizer (1) comprises a power supply circuit (11), an output control circuit (12) for outputting a high-frequency voltage whose frequency is higher than the audible frequency converted from a DC voltage generated by the power supply circuit (11) alternately to two output lines in a given cycle, a transformer circuit (13) for stepping up the high-frequency voltage, a discharge section (20) composed of 2n (n=1 or more integer) discharge needles which are used for generating positive ions by applying a positive voltage and negative ions by applying a negative voltage and are divided into a first group of n discharge needles and a second group of n discharge needles, and a polarity inverting circuit (14) for converting the high-frequency high voltage outputted from the transformer circuit (13) into two DC high rectangular voltages having different polarities for the same period, inverting the polarities of the two DC high voltages in a given cycle, and outputting the DC high voltages to the first and second groups of the discharge section (20), and a blower for sending air from the windward side of the discharge section (20). ® KIPO & WIPO 2009

Description

Antistatic Device {Neutralizer}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an antistatic device that is electrically neutral by irradiating positive ions to a charged object.

Background Art Conventionally, in cell production processes such as semiconductor manufacturing lines, mobile phones, and the like, a static eliminator is disposed in the vicinity of a workbench or a conveyor in order to prevent electrostatic interference and electrostatic adsorption by component charging. As an antistatic device used in such a manufacturing site, a positive or negative ion is discharged (irradiated) to an antistatic object (part) in which the positive or negative charge becomes excessively or partially excessively, and is electrically neutral. There is a way to do it. Such antistatic devices are classified into several types by the antistatic method. The features of each method will be briefly described below.

(1) AC type

A sinusoidal high voltage (frequency 50/60 Hz) is applied to one discharge needle to alternately generate positive ions. Since one discharge needle generates positive ions, it is characterized by a small amount of time-shifting and spatial biasing of the ion balance.

Here, ion balance shows how much the residual potential after ion irradiation falls from 0V, and it becomes an ideal characteristic that a residual potential will be normally 0 volts. Incidentally, over time ions of the ion balance means that when the static eliminator is continuously operated, there is a difference in the degree of dirt adhesion, corrosion, and abrasion of each discharge needle of the positive and negative, resulting in a bias in the residual potential. In addition, the spatial bias of ion balance means that when an ion is irradiated to a static elimination object, a difference in residual potential arises by the position of a static elimination object. The spatial bias of the ion balance is determined by irradiating ions to the static elimination objects regularly arranged at a predetermined distance from the antistatic device and measuring the residual potential at which position of the static electricity target object as described later. In addition, the amplitude of the ion balance mentioned later means that the surface potential of the static elimination object to which positive and negative ions were irradiated changes to both sides and a negative side periodically.

(2) DC type

Positive positive voltages are applied to the positive and negative discharge needles, respectively, so that positive and negative ions are generated in each discharge needle. It is difficult to recombine the released positive ions until they reach the antistatic object, and are characterized by being able to blow ions farther than AC type.

(3) AC high frequency

High frequency voltage of 20kHz ~ 70kHz is applied to one discharge needle. Compared with the general AC type, the transformer can be made lighter and smaller.

(4) pulse DC type

The positive and negative needles are alternately applied to the positive and negative needles, respectively, so that positive and negative ions are generated alternately in each discharge needle. It is a feature that the bias over time of the ion balance is improved over the general DC type. Moreover, Japanese Patent Laid-Open No. 2002-43092 (Patent Document 1) exists as the related prior art.

(5) Pulse AC

The high voltage of the square wave is applied to one discharge needle. The ion generation amount can be increased more than the general AC type, and the oscillation frequency can be made variable (refer to Patent Document 2). Moreover, Japanese Patent Laid-Open No. 2000-58290 (Patent Document 2) exists as the related prior art.

However, each of the aforementioned static elimination methods has the following problems.

(1) AC type

The transformer that generates the high voltage is heavy and large. Since this kind of static elimination device is often used on a table or suspended, it is preferable to use a small and lightweight antistatic device, but it is difficult to make the device small and light in AC type. In addition, since positive and negative ions are generated alternately, the static elimination objects are charged in an alternating positive and negative manner, and in time, amplitudes arise in the ion balance. For this reason, it is difficult to maintain the residual potential after ion irradiation near 0 volts. In addition, since the amount of positive and negative ions generated is smaller than that of the DC equation, it is inferior to the DC equation in terms of decay time characteristics and static charge range. Here, the decay time characteristic means the time after the ion irradiation until the electric potential of an antistatic object becomes an allowable level. Therefore, if the electric potential of the charged static elimination object can be lowered to an acceptable level in a short time, the decay time characteristic is excellent. The antistatic range is a spatial range in which the potential of the antistatic object can be lowered to an acceptable level by ion irradiation.

(2) DC type

In the case of continuous operation, a difference occurs in the degree of dirt adhesion, corrosion, and abrasion of the discharge needles of the positive and negative electrodes, resulting in a time bias of ion balance. In addition, depending on the position of the discharge needle, a place susceptible to the influence of cations or a place susceptible to the influence of anions is generated. For this reason, the static elimination object arrange | positioned at such a place is positively or negatively charged, and the spatial bias of ion balance arises.

(3) AC high frequency

Since the generation interval of positive and negative ions is short, it is easy to recombine until the positive and negative ions released reach a static elimination object, and it is difficult to blow ions far. In addition, since the amount of ions reached decreases, the decay time characteristics also deteriorate.

(4) pulse DC type

In the case of continuous operation, as in the case of the DC type, differences in the degree of dirt adhesion, corrosion, and abrasion of the discharge needles of the positive and negative electrodes occur, resulting in a timed bias of ion balance. In addition, since the spatial bias of the ion balance is generated in a place that is susceptible to the effects of the positive and negative discharge needles to which dirt is easily attached, or where the negative discharge needles are easily attached to the dirt, the antistatic object is positive or negative. To be charged. In addition, since positive ions are alternately generated, the static elimination objects are charged alternately in a positive manner as in the AC equation, and in time, amplitudes are generated in the ion balance.

(5) Pulse AC

Since positive and negative ions are generated alternately, the static elimination targets are charged in a positive and negative manner, and since the amount of ions generated is larger than that of the AC type, an amplitude occurs in the ion balance in time.

As described above, in the conventional static elimination device, there are any problems among size, weight, decay time characteristic, and ion balance characteristics, and the current state is that a static elimination device that solves all of these problems has not been realized.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and an object of the present invention is to provide an antistatic device which is small in size and light in weight, and has excellent decay time characteristics and ion balance characteristics.

In order to achieve the above object, a first aspect of the present invention is an antistatic device, which includes: a power supply circuit for generating a DC voltage; An output control circuit for converting the DC voltage generated in the power supply circuit into a high frequency voltage equal to or greater than an audible frequency and alternately outputting the corresponding high frequency voltage to two output lines at predetermined intervals; A transformer circuit for boosting the high frequency voltage output from the output control circuit; It consists of 2n discharge needles (an integer greater than or equal to 1) which outputs positive ions when a positive DC high voltage is applied, and outputs negative ions when a positive DC high voltage is applied. A discharge part divided into first and second groups; The high frequency high voltage output from the transformer circuit is converted into two DC high voltages of square waves having different polarities in the same period, and the polarities of the two DC high voltages are inverted at regular intervals to thereby first and second discharge parts. A polarity inversion circuit respectively outputting to the group; And a blower which blows air from the wind-up side of the discharge needle and conveys the positive and negative ions output from the discharge needles of the 2n toward the antistatic object disposed on the wind-down side. In the above configuration, in the same period, ions outputting ions of one polarity from the first group of the discharge portion, output ions of the other polarity from the second group, and output from the respective groups at regular intervals. Invert the polarity of.

The second aspect, which is dependent on the first aspect of the present invention, in the antistatic device, wherein the output control circuit outputs an output switching frequency of 10 to 100 Hz when the high frequency high voltage is alternately output to two output lines every predetermined period. It should be in the range of.

The third side surface which is dependent on the 1st side surface or the 2nd side surface of the present invention is the antistatic device, which is provided between the blower and the discharge unit and detects a pulse signal by corona discharge. It further includes a trimmer corona pulse detection means.

The fourth side surface which depends on any one side surface of the said 1st-3rd side of this invention is a said antistatic device, The guard electrode provided between the said discharge part and the antistatic object object, and connected to a ground potential is provided. It includes more.

According to the static elimination apparatus based on the said 1st side thru | or 4th aspect of this invention, since the high frequency winding transformer, piezoelectric transformer, etc. corresponding to the oscillation frequency more than an audible frequency can be used, compared with an AC type static elimination apparatus, the apparatus was compact and light weight. It can be done.

In addition, since two DC high voltages of square waves having different polarities are applied to the first and second groups of the discharge unit, the amount of positive and negative ions generated is higher than that of the AC type static eliminator, so that the decay time characteristics can be improved. . For the same reason, the static elimination range can be wider than that of the AC static eliminator.

In addition, since the positive and negative ions are generated in the same period in the discharge needle divided into two groups, the polarity of the ions output from each group is inverted for each predetermined period. The amount of positive and negative ions on the surface of the antistatic object can be made approximately equal. Therefore, neutralization of the potential is promoted, and the residual potential on the surface of the static elimination object can be reduced. As a result, the amplitude of the ion balance can be made close to zero, and the deviation of the amplitude can be reduced.

In addition to the above, since the polarity of the positive and negative ions emitted is reversed at regular intervals, and the positions at which the ions are released are also switched at regular intervals, they are not affected by either positive or negative ions depending on the position of the static elimination object. Positive ions can be irradiated to the static elimination objects at all positions almost evenly. Therefore, the spatial bias of ion balance can be made small.

Since the polarities of the positive and negative ions emitted from the discharge needles of each group are inverted at regular intervals, the degree of dirt adhesion, corrosion, and abrasion of each discharge needle is almost even even in the case of continuous operation. For this reason, the bias of the residual potential for every discharge needle does not arise, and the bias over time of an ion balance can be reduced.

1 is an overall configuration diagram of an antistatic device according to an embodiment.

2A and 2B are explanatory diagrams showing a configuration of a discharge unit.

3 is a block diagram showing a configuration of a high voltage generation circuit.

4 is a circuit diagram showing the configuration of the polarity inversion circuit.

5 is an explanatory diagram showing a configuration of an evaluation apparatus.

6A and 6B are characteristic diagrams of ion balance amplitude-time, in particular, FIG. 6A is a characteristic diagram of the static eliminator of the present embodiment, and FIG. 6B is a characteristic diagram of a pulse AC static eliminator as a comparative example.

7A and 7B are characteristic diagrams of ion balance amplitude-times by the static eliminator of the embodiment, in particular, FIG. 7A is a characteristic diagram at an output switching frequency of 1.4 Hz, and FIG. 7B is a characteristic diagram at an output switching frequency of 35 Hz.

8A and 8B are ion balance space characteristic diagrams, in particular, FIG. 8A is a characteristic diagram according to the static eliminator of the embodiment, and FIG. 8B is a characteristic diagram by the DC static eliminator as a comparative example.

EMBODIMENT OF THE INVENTION Hereinafter, the Example of the antistatic device which concerns on this invention is described based on drawing.

1 is an overall configuration diagram of a static eliminator according to the present embodiment, FIG. 2 is an explanatory diagram showing the configuration of a discharge unit, and FIG. 3 is a block diagram showing the configuration of a high voltage generation circuit.

As shown in FIG. 1, the static eliminator 1 includes a high voltage generating circuit 10, a discharge unit 20, a blower 30, a streamer corona pulse detecting electrode 40, and a streamer corona pulse signal detecting device 50. ) And a guard electrode 60. Reference numeral 70 denotes a static elimination object.

The high voltage generation circuit 10 is a circuit for simultaneously applying the DC high voltages having different polarities alternately to the discharge unit 20 at regular intervals. The configuration of the high voltage generation circuit 10 will be described later.

The discharge part 20 is comprised from the discharge needles 21-24 used as a discharge electrode, as shown in FIG. Each discharge needle outputs positive ions when a positive DC high voltage is applied, and outputs negative ions when a negative DC high voltage is applied. When the DC high voltage supplied from the high voltage generating circuit 10 is applied to the discharge needles 21 to 24, corona discharge is generated between the discharge needles 21 to 24 and the guard electrode 60 to output positive and negative ions. . The high voltage generation circuit 10 is supplied with a direct current high voltage having different polarities alternately at regular intervals.

As shown in FIG. 2, discharge needles 21-24 are arrange | positioned in four places so that a front end may face toward a center direction. Among these, discharge needles facing each other become electrode pairs (groups) that output unipolar ions. In the present embodiment, the discharge needles 21 and 23 become the first group, and the discharge needles 22 and 24 become the second group. And while one group outputs positive ions, the other group outputs negative ions at the same time, while the other group outputs negative ions simultaneously while the other group outputs positive ions.

For example, as shown in FIG. 2A, in the period A, the discharge needles 21 and 23 of the first group output negative ions, and the discharge needles 22 and 24 of the second group output positive ions. As shown in Fig. 2B, in the next period B, the discharge needles 21 and 23 of the first group output positive ions, and the discharge needles 22 and 24 of the second group output negative ions. In the same manner below, each group alternately repeats the outputs of the periods A and B for each predetermined period.

In the present embodiment, as shown in Figs. 2A and 2B, the same polarity voltage is always applied to the opposing discharge needles. In such a configuration, ion balance characteristics can be improved. Moreover, you may always apply a bipolar voltage to the opposing discharge needle. In addition, although the number of discharge needles is four in a present Example, 2n (an integer of 1 or more) may be sufficient.

In addition, the discharge needles 21-24 are arrange | positioned at substantially right angle with respect to the blowing direction (left-right direction of the ground surface) of the blower 30, as shown in FIG. The inter-pole distance K of the bipolar discharge needle is determined by the performance of spatial ion balance and the distance L between the apparatus main body and the static elimination object 70 during use. As an example, in the range of L = 150 mm to 600 mm, K = 40 mm to 120 mm is a suitable range.

The blower 30 is arrange | positioned at the wind side (upstream side) of the discharge part 20. As shown in FIG. In other words, the discharge unit 20 is disposed on the downside (downstream side) of the blower 30. The blower 30 blows air by rotating a fan (not shown) with a motor. By this blowing, the positive and negative ions output from the discharge unit 20 are conveyed to the antistatic object 70.

The streamer corona pulse detection electrode 40 is disposed between the blower 30 and the discharge unit 20, and detects the discharge current by the corona discharge of the discharge unit 20 to detect the pulse signal according to the discharge current. Outputs a (detection signal). The streamer corona pulse signal detection device 50 determines whether the discharge state of the corona discharge is normal based on the pulse signal output from the streamer corona pulse detection electrode 40. In other words, when the streamer corona pulse discharge occurs, the discharge current caused by the corona discharge changes significantly in a short time (a very steep change), and when the pulse signal corresponding to the detected discharge current exceeds a predetermined level, the corona discharge occurs. It can be judged as abnormal. In general, it is known that abnormality of corona discharge increases due to dirt deposition on discharge needles. For this reason, since the cleaning timing of a discharge needle can be known correctly by providing the apparatus which detects the abnormality of corona discharge, maintenance can be reliably performed. The streamer corona pulse detection electrode 40 and the streamer corona pulse signal detection device 50 function as the streamer corona pulse detection means in this embodiment.

The guard electrode 60 is for preventing the operator's finger or the like from touching the discharge needle to which the high voltage is applied, and is disposed between the discharge unit 20 and the antistatic object 70. The guard electrode 60 is connected to the ground potential, and also functions as a counter electrode of each discharge needle. The guard electrode 60 is preferably formed of a conductor such as metal in order to reduce the voltage variation of the antistatic object 70 caused by induction. In addition, although the structure of the guard electrode 60 arrange | positions ring-shaped metal electrode concentrically, etc. are used, it is not limited to this example, It is easy to let an ion pass while it is space | interval enough that an operator's finger does not enter. The interval between them is secured. Moreover, it is preferable to arrange | position the guard electrode 60 so that it may become distance M (<interval distance K) between discharge needles. When the corona discharge is started in the discharge unit 20, since the potential difference between the guard electrode and the discharge needle is larger than the potential difference between the discharge needles, the generated positive and negative ions fly toward the guard electrode 60. At this time, if the guard electrode 60 is present, positive and negative ions can be trapped, so that the decay time characteristic is slightly reduced. However, by providing the guard electrode 60, the amplitude of the ion balance can be greatly reduced.

Next, the configuration of the high voltage generation circuit 10 will be described. As shown in FIG. 3, the high voltage generation circuit 10 includes a DC power supply circuit 11, an output control circuit 12, a transformer circuit 13, and a polarity inversion circuit 14.

The DC power supply circuit 11 is a circuit which is connected to an AC power supply (not shown) [AC 100V] and converts an AC voltage into a DC voltage (DC 12V) and outputs it.

The output control circuit 12 converts the DC voltage output from the DC power supply circuit 11 into a high frequency voltage equal to or higher than the audible frequency (20 KHz or higher) and connects the high frequency voltage to the transformer circuit 13. The outputs of two systems are alternately switched at regular intervals. In this embodiment, the output switching frequency at the time of alternately outputting the high frequency voltage to the two system output lines every fixed period is set in the range of 10 to 100 Hz. For example, when the output switching frequency is set to 50 Hz, since one cycle becomes 0.02 s, the semi-period 0.01 s becomes the predetermined period.

In this embodiment, the output switching frequency when alternating high frequency voltages are output to two output lines is in the range of 10 to 100 Hz, so that the polarity of the positive ions output from the discharge needles of each group is also the output switching frequency. It is reversed every certain period of time. According to this, since the generation interval of positive ion can be made long, compared with an AC high frequency type static eliminator, it is difficult to recombine the positive ion discharge | released until it reaches a static elimination object, and the ion can be blown far.

The transformer circuit 13 is composed of a high frequency winding transformer or a piezoelectric transformer corresponding to an oscillation frequency of 20 kHz or more, and boosts the high frequency voltage output from the output control circuit 12 to output as a high frequency high voltage. It is a circuit. The transformer circuit 13 of the present embodiment is composed of transformers L1 and L2, and high-frequency voltages are alternately outputted at predetermined periods in these transformers L1 and L2. The output side of the transformer circuit 13 is connected to the polarity inversion circuit 14 and two output lines, and the high frequency voltage output from the transformers L1 and L2 is alternately output to the polarity inversion circuit 14 at each output line. do.

In the present embodiment, since the transformer circuit 13 is constituted by a high-frequency winding transformer or a piezoelectric transformer corresponding to an oscillation frequency of 20 kHz or more, the device is smaller and lighter than the AC type static eliminator. It can be done.

The polarity inversion circuit 14 converts the high frequency high voltages alternately outputted by the transformer circuit 13 every fixed period into two DC high voltages of square waves having different polarities in the same period, and at the same time, polarities of the two DC high voltages. Is inverted every predetermined period and output to the first and second groups of the discharge unit 20. That is, when outputting the positive DC high voltage to the first group, when outputting the positive DC high voltage to the second group, and outputting the negative DC high voltage to the first group, the positive DC high voltage to the second group Will print at the same time.

In this embodiment, two direct current high voltages of square waves having different polarities are applied to the first and second groups of the discharge section 20. According to this, since the amount of positive and negative ions generated can be increased as compared with the AC type static eliminator, the potential of the charged static elimination object can be lowered to an acceptable level in a short time, and the decay time characteristic can be improved. In addition, it is possible to widen the range of static elimination as compared to the AC type static eliminating device in which the amount of positive ion is generated.

Next, the configuration and operation of the polarity inversion circuit 14 will be described. 4 is a circuit diagram showing the configuration of the polarity inversion circuit. As shown in FIG. 4, the polarity inversion circuit 14 is comprised by the rectifier circuit which consists of capacitor | condenser C1-C8, resistor R1-R4, and diode D1-D8. The rectifier circuits are alternately supplied with a high frequency high voltage as indicated by the inputs A and B in the transformers L1 and L2 every predetermined time. In the rectifier circuit, the input high frequency high voltage is rectified to be a DC high voltage and output from the output terminals indicated by the outputs A and B.

When the input A is supplied from the transformer L1 (in this period, the input B is zero), this input A is rectified in the rectifying circuit, and then the output A is of negative voltage (output A). The square wave of the center part of is output, and the bipolar voltage (square wave of the center part of the output B) is output to the output B, respectively. Also, if the input B is supplied from the transformer L2 in the following period (in this period, the input A is zero), the input B is rectified in the rectifying circuit, and then the output A is bipolar. The voltage (square wave on the right side of the output A) is output to the output voltage B and the negative voltage (square wave on the right side of the output B) is output. As described above, when the high frequency high voltages of the inputs A and B are alternately supplied from the transformers L1 and L2 at regular intervals, the high frequency high voltage input is rectified and smoothed in the polarity inversion circuit 14, and at the same time, for each period. This is inverted and output to the outputs A and B. Since the discharge needles 21 and 23 of the first group are connected to the output A, and the discharge needles 22 and 24 of the second group are connected to the output B, the ions outputted from the respective groups. The polarity of is reversed every fixed period.

That is, as shown in FIG. 2A, in the period A, negative ions are output in the discharge needles 21 and 23 of the first group, and positive ions are simultaneously output in the discharge needles 22 and 24 of the second group. In addition, as shown in FIG. 2B, in the next period B, positive ions are output in the discharge needles 21 and 23 of the first group, and negative ions are simultaneously output in the discharge needles 22 and 24 of the second group. . And since the polarity of the ion output from each group is inverted every fixed period, the discharge needle of each group outputs the ion of different polarity every fixed period.

Next, the ion balance characteristic of the antistatic device configured as described above will be described.

The evaluation method based on EOS / ESD standard St 3.1 is generally used for evaluation of this kind of static eliminator. 5 is an explanatory diagram showing a configuration of an evaluation apparatus used in the above measuring method. The evaluation apparatus 100 arranges the charging plate to be a static elimination object on the substrate 2 at the measuring points of TP1 to TP12 in turn, and arranges the antistatic device 1 at a position of 300 mm from the measuring point of TP2. will be. Moreover, the charging plate is comprised by the member of 150 mm x 150 mm in length and breadth, and a capacity | capacitance of 20 pF.

Each charged plate is provided with a potential-contacting sensor not shown and a charging electrometer connected with the potential sensor. In addition, each of the charging plates is connected with a +1 kV high voltage power supply and a -1 kV-high voltage power supply (not shown) for charging the charging plate when measuring the decay time. In addition, there is also a digital display device for displaying a timer, time, and the like, which are not shown, which time the decay time.

(1) ion balance amplitude-time characteristics

6 is a characteristic diagram of ion balance amplitude-time. 6A is a characteristic diagram according to the static eliminator of the present embodiment, and FIG. 6B is a characteristic diagram by the pulse AC static eliminator as a comparative example. This evaluation method removes the residual charge of each charge plate, irradiates ions to the charge plates TP1-12 from the antistatic device 1, and measures the plate potential [V] after a fixed time. In this example, the distance between the antistatic device 1 and the charging plate is made close to 150 mm. This is to make the influence of the ion balance amplitude-time characteristic more remarkable.

In the static eliminator 1 of the present embodiment, since the positive and negative ions are simultaneously generated in the same period by the discharge needles divided into two groups, the polarity of the ions output from the respective groups is inverted at regular intervals. While the polarity of the positive and negative ions to be reversed every fixed period, the position at which the ions are released is also switched every fixed period. According to this, since positive ions generate | occur | produce simultaneously in the same period, the amount of positive ions on the surface of a charging plate becomes substantially the same. Therefore, neutralization of the potential is promoted, and the residual potential on the surface of the charging plate can be reduced. As a result, as shown in FIG. 6A, the amplitude of the ion balance can be made close to zero, and the deviation of the amplitude can be reduced. Therefore, even if the static elimination device 1 of the present embodiment has a close distance to the static elimination object, there is little amplitude and bias of the ion balance, so that uniform static elimination is possible over the work table or the entire conveyor.

On the other hand, in the pulse AC type static eliminator of the comparative example, since positive and negative ions are alternately generated, the charging plate is charged alternately with positive and negative ions, and since the amount of generated ions is higher than that of the AC type, as shown in FIG. Amplitude occurs. In particular, when the distance between the static eliminator and the charging plate is made close as in this evaluation method, both amplitude and bias become large.

Here, a cycle for inverting the polarity of the ions output from the first and second groups will be described. In this embodiment, the output switching frequency is 10 to 100 Hz when the high frequency voltage is alternately switched to two system output lines. FIG. 7 is a characteristic diagram of ion balance amplitude-time as shown in FIG. 6, all of which are characteristic charts of the static eliminator of the present embodiment. 7A is a characteristic diagram at an output switching frequency of 1.4 Hz, and FIG. 7B is a characteristic diagram at an output switching frequency of 35 Hz.

As shown in FIG. 7A, when the polarity is inverted at a cycle specified at the output switching frequency 1.4 Hz, the residual potential on the surface of the charging plate cannot be reduced, and the amplitude of the ion balance increases. In the case where the output switching frequency is set to 100 Hz or more, although it is not shown in the figure, it is difficult to carry the ions far away as in the high frequency type, and the decay time characteristic is also worsened. On the other hand, as shown in FIG. 7B, when the polarity is inverted at a cycle defined at the output switching frequency 35 Hz, the residual potential on the surface of the charging plate can be reduced, and the amplitude of the ion balance can be further reduced.

(2) ion balance space characteristics

8 is an ion balance space characteristic diagram. 8A is a characteristic diagram according to the static eliminator of the present embodiment, and FIG. 8B is a characteristic diagram by the DC static eliminator as a comparative example. The X axis of FIG. 8 is a plate potential [V], the Y axis is a left and right distance [mm] centering on the charging plate TP2 at the center of the most heat transfer, and the Z axis is a distance [mm] in the depth direction from the static eliminator. Are respectively shown (refer FIG. 5).

In the antistatic device 1 of the present embodiment, since the polarity of the positive and negative ions emitted is reversed every fixed period, and the positions at which the ions are released are also switched every fixed period, either positive or negative depending on the position of the charging plate. A positive ion can be irradiated almost uniformly on all the charging plates without being affected by the ion. Therefore, as shown in FIG. 8A, the spatial bias of ion balance can be made small.

On the other hand, in the DC type static eliminating device of the comparative example, since the place which is easily affected by the cation or the place which is easy to be affected by the anion is generated depending on the position of the discharge needle, the DC static elimination device is disposed at a place that is easily affected by either of these amounts or anions. In the charging plate, it is charged positively or negatively. For this reason, as shown to FIG. 8B, the spatial bias of ion balance will generate | occur | produce. In FIG. 8B, the charging plates (TP2, TP3, etc. in FIG. 5) disposed at positions close to the static eliminator are charged to the bipolar side.

(3) ion balance over time characteristics

In the antistatic device 1 of this embodiment, since the polarity of the positive and negative ions emitted from the discharge needles 21 to 24 of each group is inverted at regular intervals, dirt adhesion and corrosion of each discharge needle even in the case of continuous operation. The degree of wear is nearly even. For this reason, the bias of the residual potential for every discharge needle does not arise, and the bias over time of an ion balance can be reduced. After continuously operating the antistatic device 1 of this embodiment for a predetermined period of time, the tip portions of the discharge needles were observed, and it was confirmed that the degree of dirt adhesion, corrosion, and abrasion of the tip portions became almost equal (shown in the measurement results). skip).

In addition to the ion balance characteristics, the decay time characteristics were also measured. In the static eliminator 1 of the present embodiment, the amount of positive and negative ions can be increased as compared with an AC type or an AC high frequency type, and thus the decay time characteristic can be improved. In order to verify this decay time characteristic, the charged plate charged with the high voltage of +1 kV was ion-excited using the electrostatic discharge device 1 of this Example, and it measured about the time which plate potential decays to + 100V. As a result, it was confirmed that the attenuation time is shorter than that of the AC or AC high frequency type, and the result is almost the same as that of the DC type (not shown in the measurement results).

In addition, since the amount of positive and negative ions can be increased in comparison with the AC type static eliminator, the static elimination range can be widened. This antistatic range can also be confirmed from the result of the ion balance space characteristic shown in FIG. 8A.

As described above, in the static elimination device 1 according to the present embodiment, since the transformer circuit is constituted by a high frequency winding transformer or a piezoelectric transformer corresponding to the oscillation frequency of 20 kHz or more, the AC circuit is used. The device can be made smaller and lighter than the static eliminator.

In addition, since two DC high voltages of square waves having different polarities are applied to the first and second groups of the discharge unit 20, the amount of positive and negative ions generated can be increased compared to the AC type static eliminator, and the decay time is reduced. Properties can be improved. For the same reason, the static elimination range can be wider than that of the AC static eliminator.

In addition, in the antistatic device 1 of the present embodiment, positive and negative ions are simultaneously generated in the same period by the discharge needles divided into two groups, and the polarities of the ions output from each group are inverted at regular intervals. At the same time, the polarity of the positive and negative ions emitted is reversed at regular intervals, and the position at which the ions are released is also switched at regular intervals. Thereby, since positive ions generate | occur | produce simultaneously in the same period, the amount of positive ions on the surface of a charging plate becomes substantially the same. Therefore, neutralization of the potential is promoted, and the residual potential on the surface of the charging plate can be reduced. As a result, the amplitude of the ion balance can be made close to zero, and the deviation of the amplitude can be reduced.

In addition, in the static elimination device 1 of the present embodiment, since the polarity of the positive and negative ions emitted is reversed every fixed period, and the position at which the ions are released is also switched every fixed period, either positive or negative depending on the position of the static elimination object. A positive ion can be irradiated almost uniformly to all the charging plates without being influenced by one ion. Therefore, the spatial bias of ion balance can be made small.

In addition, in the antistatic device 1 of the present embodiment, since the polarity of the positive and negative ions emitted from the discharge needles of each group is inverted at regular intervals, dirt discharge, corrosion and abrasion of each discharge needle even in a continuous operation. The degree of is nearly even. For this reason, the bias of the residual potential for every discharge needle does not arise, and the bias over time of an ion balance can be reduced.

In addition, in the static eliminator 1 of the present embodiment, the output switching frequency when alternating high frequency voltages are output to two system output lines is in the range of 10 to 100 Hz, so that the interval between the generation of positive and negative ions can be increased. have. For this reason, compared with the AC high frequency static elimination device, the positive and negative ions released are less likely to recombine until they reach the static elimination object, and the ions can be blown far.

In the static elimination device 1 of the present embodiment, the streamer corona pulse detection electrode 40 is used as the streamer corona pulse detection means for detecting the pulse signal caused by corona discharge between the blower 30 and the discharge unit 20. Since the over streamer corona pulse signal detection device 50 is provided, the timing of cleaning the discharge needle can be accurately known, and the maintenance can be surely performed.

In addition, in the antistatic device 1 of the present embodiment, since the guard electrode 60 is provided between the discharge unit 20 and the antistatic object 70, the amplitude of the ion balance can be greatly reduced.

The present invention is not limited to the description of the above-described embodiments of the invention except for those described above, and can be implemented in various other aspects by appropriate modifications.

In addition, all the content of the Japan patent application 2006-341803 (December 19, 2006 application) is integrated in this specification by reference.

Claims (4)

In the antistatic device, A power supply circuit for generating a DC voltage; An output control circuit for converting the DC voltage generated in the power supply circuit into a high frequency voltage equal to or greater than an audible frequency and alternately outputting the corresponding high frequency voltage to two output lines at predetermined intervals; A transformer circuit for boosting the high frequency voltage output from the output control circuit; It consists of 2n discharge needles (an integer equal to or greater than 1) which outputs positive ions when a positive DC high voltage is applied, and outputs negative ions when a positive DC high voltage is applied, and each of these discharge needles is the first And a discharge part divided into a second group; The high frequency high voltage output from the transformer circuit is converted into two DC high voltages of square waves having different polarities in the same period, and the polarities of the two DC high voltages are inverted at regular intervals to the first and second groups of the discharge unit. A polarity inversion circuit for outputting each; And And a blower which blows air from the wind-up side of the discharge needle and conveys the positive and negative ions output from each of the 2n discharge needles toward an antistatic object disposed on the wind-down side. In the same period, the first group outputs ions of one polarity, the second group outputs ions of the other polarity, and inverts the polarity of the ions output from the respective groups every predetermined period. Antistatic device. The method of claim 1, The output control circuit is an antistatic device, characterized in that the output switching frequency when the high frequency high voltage is alternately output to two output lines in a range of 10 ~ 100Hz. The method of claim 1, And a streamer corona pulse detecting means provided between the blower and the discharge part and detecting a pulse signal due to corona discharge. The method of claim 1, And a guard electrode provided between the discharge portion and the antistatic object and connected to a ground potential.

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